The present disclosure relates to a media access control (MAC) filtering apparatus for high speed switching and more particularly, to a technology to determine by using hardware whether to re-transmit received data when performing Ethernet communication to transmit data through high speed switching.
In general, there are many kinds of topology including a bus topology, a tree topology, a star topology, a ring topology, and a mesh topology.
Among others, the ring topology is a closed loop topology having no start and end points, unlike the bus topology.
Thus, the ring topology does not need a terminator and transmits data in a different method from that of the bus topology. That is, only a point having a token circulating in a ring may transmit data.
It is a means for preventing a collision in the ring topology.
The point having the token transmits the token along with data to a target device.
However, since data is transmitted only in one direction in this form, it takes a long time to transmit the data to a point before a start point.
Also, a node fault affects the entire topology.
There is a dual-ring topology in which nodes are connected using two rings in order to solve such a limitation.
That is, this form enables two-way transmission in addition to one-way transmission and provides redundancy.
Thus, even if one node has a fault, it is possible to transmit data to another node and thus, the dual-ring topology is more stable than a single ring topology. A technology for enabling data to be more quickly transmitted has been proposed for the dual-ring topology.
In order to transmit data received on the Ethernet to another node in the related art, data is stored in a memory by using the RX state machine, receive buffer 21, and receive direct memory access (DMA) 22 of Ethernet MAC, and then stored data is compared with fields such as destination address, source address and Ethernet type by using software to determine a frame to be transferred, as shown in FIG. 1.
When there is a frame to be transmitted, it is possible to transmit data from a memory to a transmit buffer through transmit DMA 24 to provide a Tx state command to a transmit state memory 26 to transmit the frame.
As such, according to a typical transmission method, since a receive frame is received, determined by using software, and then re-transmitted, many resources and much time are consumed.
Such general Ethernet reception and transmission perform operations as shown in FIG. 1.
Receive data being a digital signal is received from a physical layer 1, stored in the receive buffer 21 of the MAC 2 and then stored in a higher memory through a system bus. Stored data is processed in a higher program, data to be transmitted is generated to be stored in the transmit buffer 25 through a system bus and then, transmit data is transmitted to the physical layer 1 according to the control of the MAC to complete transmission.
If a typical Ethernet system is not a switch but a general device, Ethernet receive functions all need to be activated to store a frame in a memory and perform MAC filtering through software in order to receive data (frame) and then transmit the data to another node and Ethernet transmit operations and order need to be maintained in order to transmit the data to another node.
Since such a typical Ethernet system needs frame reception, MAC filtering through software and transmission, much time and many physical resources are consumed.